Field of the Invention
This invention is directed to a new process for organic compounds and is particularly concerned with a process for 1-[2-(dimethylamino)ethyl]-6-phenyl-4H-s-triazolo[4,3-a][1,4]benzodiazepin es and novel intermediates therefor.
The novel compounds and the process of production therefor can be illustratively represented as follows: ##SPC3##
Wherein R.sub.1 is hydrogen or alkyl of 1 to 3 carbon atoms, inclusive; wherein R.sub.2 is hydrogen, chloro, or fluoro; wherein R.sub.3 is hydrogen or fluoro with the proviso that R.sub.3 is not fluoro if R.sub.2 is chloro; wherein R.sub.4 is hydrogen, fluoro, chloro, bromo, trifluoromethyl, and nitro.
The invention also embraces the pharmacologically acceptable acid addition salts of the new compounds of formulae II and III.
The process of this invention comprises: treating a compound of formula I in formic acid solution with at least 3 equivalents of formaldehyde at reflux temperature to obtain compound II; treating compound II with phthalimide, triphenylphosphine and a proton acceptor such as diethyl azodicarboxylate, in an inert organic solvent, at 0.degree. to 100.degree. C., to give compound III and treating compound III with an acid or a base, with hydrazine preferred, to produce hydrolysis and cyclization and to give product IV above.